Providing assistance to GNI in maintaining their Transmission Gas Network


The project involved the isolation, decommissioning, removal, inspection, overhaul and reinstatement of Waterbath heaters on various GNI AGI sites within the ROI. These Waterbath heaters ranged in size from 4ton units with a fluid volume of 3000ltrs operating to a design pressure of 114bar to 26ton units with a fluid volume of 44000ltrs operating to a design pressure of 220bar. All the works where carried out in live operational high pressure gas installations with overhauling, pressure testing revalidation and specialist NDT being carried out at our bespoke testing facility in Newbridge.


Decommissioning, revalidation and commissioning of units carried out in line the GNI design requirements.

Removal of bulk heads and pipework sections with lifts in excess of 13ton within live operational high-pressure gas installations ensuring that operational continuity was maintained with no interruption to supply.

Lifting operations took place under fully permitted conditions ensuring that the integrity of the network was maintained at all times.

Work was carried out to strict project program constraints with minimal downtime permitted for each of the heater units, with a typical overhaul period of 15 days from isolation of the system from the network to recommissioning back into operation.

This was made possible due to our dedicated testing facility in Newbridge which allowed for the high risk activities of Radiography and high Pressure testing to be undertaken safely and simultaneously with other inspection activities and NDT operations (UT, MPI, DPI) on the various components (gas tubes, fire tubes, burner box) within separate areas of the facility at the same time.


The safe removal, storage and reuse of Glyco products from the main heater tanks was a key environmental constraint on the project. Murphy commissioned the use of bespoke storage tanks that had the capacity to hold the large volumes of product safely on site. This removed the risk of having to transport or double handle the product minimising the risk of any loss of containment.


  • Removal, Storage and Reuse of over 80,000ltr of Glycol
  • Removal of assemblies of up to 14ton
  • Set up off mobile cranes up to 300t within restricted operational sites
  • Work carried out accident free
  • No disruption to the GNI Transmission Network

Sign up to our newsletter

Our e-newsletter provides insights into our organisation, including new business activities, key updates, projects and expertise. Subscribe today!